Two new iridoid glycosides from Gardeniae Fructus

Two new iridoid glycosides, genipin 1,10-di-O-alpha-L-rhamnoside (1) and genipin 1,10-di-beta-D-xylopyranoside (2), along with thirteen known compounds (3-15) were isolated from Gardeniae Fructus. Their structures were elucidated by physical data analyses such as NMR, UV, IR, HR-ESI-MS, as well as chemical hydrolysis. All compounds were tested for their tyrosinase inhibitory and antioxidant activities. At a concentration of 25 mu M, compound 13 showed obvious mushroom tyrosinase inhibition activity with % inhibition value of 36.52 +/- 1.98%, with kojic acid used as the positive control (46.09 +/- 1.29%). At a concentration of 1 mM, compounds 8 and 9 exhibited considerable DPPH radical scavenging activities, with radical scavenging rates of 48.54 +/- 0.47%, 58.59 +/- 0.39%, respectively, with L-ascorbic acid used as the positive control (59.02 +/- 0.77%).

Automated summary

Two new iridoid glycosides, along with thirteen known compounds, were isolated from Gardeniae Fructus. Their structures were elucidated by various analyses. All compounds were tested for their tyrosinase inhibitory and antioxidant activities, with some showing significant effects.